Related parties (Details) (ArmaGen, USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014
ArmaGen
Related Party Transaction [Line Items]
Amount paid for an equity stake and the license to develop and commercialize AGT-182	$ 15.0
Share of R&D costs recorded within R&D expense	1.7
Related parties, acrrued liabilities	$ 1.0
Percentage of equity stake	18.00%

Carrying amount as of the balance sheet date of obligations due all related parties. For classified balance sheets, represents the current portion of such liabilities (due within one year or within the normal operating cycle if longer).

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

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-Subparagraph (SX 210.4-08.(k)(1))

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 08

-Paragraph k

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

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-Name Regulation S-X (SX)

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Reference 5: http://www.xbrl.org/2003/role/presentationRef

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- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 323

-SubTopic 10

-Section 50

-Paragraph 3

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Amount of transactions with related party during the financial reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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Expenses recognized resulting from transactions (excluding transactions that are eliminated in consolidated or combined financial statements) with related party.

+ References

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